Don't throw an exception if view == window
Don't throw an exception if view == window

This happens when snapshotting the key window.
This was introduced by #137.
Ruenzuo/ios-snapshot-test-case,nap-sam-dean/ios-snapshot-test-case,Nuglif/ios-snapshot-test-case,material-foundation/ios-snapshot-test-case,material-foundation/ios-snapshot-test-case,Ruenzuo/ios-snapshot-test-case,Ruenzuo/ios-snapshot-test-case,nerdishbynature/ios-snapshot-test-case,nap-sam-dean/ios-snapshot-test-case,onemedical/ios-snapshot-test-case,facebook/ios-snapshot-test-case,nerdishbynature/ios-snapshot-test-case,peacemoon/ios-snapshot-test-case,nerdishbynature/ios-snapshot-test-case,nap-sam-dean/ios-snapshot-test-case,material-foundation/ios-snapshot-test-case,peacemoon/ios-snapshot-test-case,facebook/ios-snapshot-test-case,Nuglif/ios-snapshot-test-case,onemedical/ios-snapshot-test-case,facebook/ios-snapshot-test-case,peacemoon/ios-snapshot-test-case,Nuglif/ios-snapshot-test-case,onemedical/ios-snapshot-test-case,material-foundation/ios-snapshot-test-case